The purpose of this project is to study the Sensory-Decision-Theory Method in determining sensory discriminability and response bias in the response of experimental pain. The result of investigation of the parametric approach for the evaluation of pain response components (Clark, 1971) has been reported at the Second World Congress on Pain 1978. The investigation of the nonparametric estimation of the indices of pain response (Pollack 1964, Hodos, 1971, McNicol 1972) and the sampling behavior of these statistical indices has been broadly studied. Further work includes a cooperative study with the researchers of Columbia University Medical School Department of Anesthesiology in conducting an analgesic study to verify the investigative results.